How Does a Time Change Affect You?

· September 27, 2018

Two weekends per year, a good part of the northern hemisphere undergoes a time change in order to take better advantage of daylight hours. It’s actually an old idea. It was first proposed by Benjamin Franklin in 1784 with the goal of reducing the consumption of candles and oil lamps.

Despite this, the time change was not legally established until 1974 in most western countries. In Spain, this change was legally established in 2002 through a Royal Decree. In principle, it was supposed to be renewed every five years. Yet since its entry into the European Union, this practice seems to have extended to an indefinite duration.

Although some experts argue over the effectiveness of time changes, this custom has become so deeply rooted in our lives that we can’t just stop it out of the blue. Nevertheless, do we really know how a time change affects our bodies? In this article, we’ll tell you what science has to say about this.

How a time change affects your body

According to experts, your body doesn’t adapt very well to time changes. When you “go forward” or “go back” one hour, your circadian rhythm is altered in such a way that a series of negative effects can be produced. These changes to the circadian rhythm principally appear when you travel to another time zone. However, you might consider a time change to be equivalent to moving one time zone. It might be to the east (in the case of going forward one hour) or to the west (in case of going back one hour).

Scientists have discovered that other factors can also alter your circadian rhythm. For example, this can happen when you sleep late on the weekends or don’t keep a regular sleeping cycle. As such, even if the effect of changing the time by one hour is perceptible, it’s not an isolated issue.


woman tired because time change

Some of the most significant consequences of time changes tend to be the following:

Let’s take a look at each one of these.

1- Higher probability of traffic accidents

One of the most surprising studies related to time changes was conducted in 1999 by John Hopkins at Stanford University. In this study, it was observed that the possibility of suffering a traffic accident increased by 5% the Monday after a time change.

Another study financed by the University of Colorado found that the results were even more worrisome. They discovered a 17% higher probability. Despite the fact that the time appears to have nothing to do with accidents, the data doesn’t lie. But why is there such an increase?

The increase in traffic accidents after a time change might be explained by a hormone called melatonin. This hormone is in charge of regulating sleep cycles. It’s one of the primary hormones responsible for you feeling alert in the mornings. As such, when there’s a sudden change in your sleep pattern, you’ll feel more tired and less alert throughout the day.

2- An increase in the number of heart attacks

Similarly, a 2012 University of Alabama study suggested that there was an increase in the number of heart attacks 3 days after a time change. Other studies also show a small increase in the number of strokes.

What is the cause of these phenomena? Apparently, losing an hour of sleep wreaks havoc in your body. There is an increase in cortisol, the immune system doesn’t work as effectively as it should, and an energy reduction. These problems aren’t dangerous for the general population. However, in the case of someone with a preexisting risk of suffering such ailments, they might turn into catalysts for a heart attack or stroke.

3- More cases of depression

Finally, some studies show that time changes could be related to seasonal depression. This condition is related to the lack of exposure to sunlight. This could affect your physical or mental health.

woman headache time change

When there’s a time change, the number of hours you’re exposed to the sun could also change. On the other hand, these time change effects are often confused with those of increased temperature. However, there’s no doubt that these changes take some getting used to.